In a tuckshop,
49 of the boys wore vests. After 128 boys who wore vests entered the tuckshop, the percentage of boys who wore vests increased to 80%. How many boys in the tuckshop did not wear vests?
| |
Wore vests |
Did not wear vests |
| Before |
4x1 =
4 u |
5x1 =
5 u |
| Change |
+ 128 |
|
| After |
4x5 =
20 u |
1x5 =
5 u |
80% =
80100 =
45The number of boys who did not wear vests remains unchanged. LCM of 5 and 1 is 5.
Number of boys who wore vests and left
= 20 u - 4 u
= 16 u
16 u = 128
1 u = 128 ÷ 16 = 8
Number of boys who did not wear vests
= 5 u
= 5 x 8
= 40
Answer(s): 40
